[Lazarus] Multi-threading support in IDE

[Mattias Gärtner]

Zitat von Martin <lazarus at mfriebe.de>:

> Mattias Gärtner wrote:
>> Zitat von Vincent Snijders <vsnijders at vodafonevast.nl>:
>>>>> I like Florian's idea too. As for your statement above, how  
>>>>> often does this really happen? In the last 4-5 years that I have  
>>>>> been using FPC, the compiler has not once "crashed" on me. Yes  
>>>>> it might report that there is a compiler error in my project,  
>>>>> but I do not consider that a crash.
>>>>
>>>> The compiler is started on every compile which is the cleanest  
>>>> start you can get. A threaded compiler must have a restart, which  
>>>> is less clean. There will be more crashes and bugs.
>>>> What happens if the restart fails?
>>>
>>> For the debugger, we have reset debugger.
>>> For the compiler, we would add a reset compiler option.
>>
>> I meant, when the compiler is in another thread and the restart  
>> fails, what should happen? You can only restart the IDE.
>
> Just out of curiosity, what are we trying to solve?
>
> How much benefit would a build in or preloaded fpc inside Lazarus  
> be? Most Operating System cache disk access. So once you used, it is  
> in memory, never mind if that memory belongs to lazarus, or the OS.
>
> Of course another thread would solve issues with unresponsiveness.  
> But that could be done by having another thread, that runs the  
> external process. Or if the AsyncProcess worked, it could be done,  
> by using this + moving to an event-driven model.
>
> Or am I missing some crucial point?

Well, the crucial points speak all against an internal compiler as thread.
But an internal compiler can have some benefits:
Access to the compiler structures may allow to find out, why a "unit  
was not found". But I doubt that.
Access to the compiler structures may allow to do a find declaration  
in ppu files. But reading ppu files is not a big problem. I already  
started that in the codetools. The problem is to make the information  
usable to the existing tools (identifier completion). And this is a  
lot of work.

My conclusion:
Let's use an external compiler as Florian proposed and one day the  
ppus don't need to be parsed on every compile. This should reduce the  
compile time dramatically.

Mattias